Purpose: The purpose of this study was to develop a web-based tool for the estimation of dose to primarily irradiated radiosensitive organs in pediatric and adult computed tomography (CT) examinations.
Methods: Thoracic CT data from 97 pediatric patients and 203 adult individuals, with well-defined clinical indications, were included in this study. Patient-specific voxelized phantoms were used as input in a Monte Carlo (MC) dosimetry software to generate three-dimensional (3D) dose distributions. Three CT scanner models were modeled. Organ dose information was extracted from 3D dose distributions through delineation. This methodology allowed the development of a web-based tool for the estimation of organ doses from pediatric and adult chest CT examinations. Organ doses derived from dose distributions were normalized and correlated with patients’ water-equivalent-diameter (WED) using non-linear regression analysis. Doses estimated using MC data were compared to those determined using thermoluminescence dosimetry, 1 adult, and 4 pediatric anthropomorphic phantoms.
Results: Normalized organ doses demonstrated a good correlation with WED (R²=0.7-0.9, P<0.001 for all cases). The regression coefficient matrix was integrated into the web-based tool to provide the required organ dose values. User input fields were organized into three groups. WED information can be directly inserted into the web tool or calculated from patient images. Information about the exposure settings and clinical indication for the CT examination is provided by the user in a separate tab. The estimated dose values were normalized to CTDI free-in-air or volume based on user selection. A very good agreement was found between organ doses estimated by thermoluminescence dosimetry and the MC simulation (differences up to 19.2%).
Conclusion: Estimation of organ doses from pediatric and adult chest CT examinations can be made using a web-based tool. This tool is available upon free user registration. An extended verification study of the web-based tool output is currently in progress.
Funding Support, Disclosures, and Conflict of Interest: This study has received funding from the research and training programme 2014-2018 under grant agreement No 755523 (MEDIRAD project) and the Hellenic General Secretariat for Research and Innovation (KA 4929).